Non-aqueous electrolyte secondary battery

Abstract

This non-aqueous electrolyte secondary battery that is an example of an embodiment comprises a winding type electrode body for which a positive electrode and a negative electrode are wound with a separator interposed. The electrode body has a positive electrode lead. The positive electrode lead has: a lead base made of metal that includes a first surface joined to the positive electrode, and a second surface on the side opposite to the first surface; and an insulating ceramic layer principally comprising an inorganic compound and formed over a range within the second surface of the lead base so as to face the negative electrode with at least the separator interposed therebetween.

The invention claimed is: 
     
       1. A non-aqueous electrolyte secondary battery comprising:
 a spiral-type electrode body in which a positive electrode and a negative electrode are wound with a separator located therebetween; 
 a bottomed cylindrical outer can that holds therein the electrode body; and 
 a sealing body that closes off an opening of the outer can and that functions as a positive electrode terminal, wherein 
 the electrode body has a positive electrode lead which has a first end portion being one lengthwise end of the positive electrode lead, and a second end portion located toward a side opposite to the first end portion, the second end portion being the other lengthwise end of the positive electrode lead; 
 the positive electrode lead comprises:
 only a single lead base member made of metal and having a first surface joined to the positive electrode, and a second surface located on an opposite side of the first surface; and 
 an insulating ceramic layer composed only of an insulating inorganic compound or comprising the inorganic compound and a binder which binds particles of the inorganic compound wherein a content of the binder is from 1 to 10% by mass relative to the mass of the inorganic compound, the ceramic layer being formed directly on the second surface of the single lead base member in at least an area facing the negative electrode via the separator, 
 
 the ceramic layer is formed over the entire area facing the negative electrode via the separator, and additionally in the first end portion on the second surface of the single lead base member, wherein the ceramic layer in the first end portion is formed only within a range of 3 mm from a first end; and 
 the single lead base material includes, on the second surface thereof a region which is sandwiched between the ceramic layer formed in the first end portion and the area facing the negative electrode via the separator, and is not covered by the ceramic layer, the region being a region where a welded portion which is welded to the sealing body is formed. 
 
     
     
       2. The non-aqueous electrolyte secondary battery according to  claim 1 , further comprising
 an upper insulation plate disposed between the sealing body and an electrode group constituted of the positive electrode, the negative electrode, and the separator, the upper insulation plate having an insertion hole for the positive electrode lead. 
 
     
     
       3. The non-aqueous electrolyte secondary battery according to  claim 1 , wherein
 the negative electrode comprises a negative electrode core and a negative electrode mixture layer formed on the negative electrode core; 
 an exposed core portion in which a surface of the negative electrode core is exposed is provided on an outermost peripheral surface of the electrode body; and 
 the exposed core portion is in contact with an inner peripheral surface of the outer can. 
 
     
     
       4. The non-aqueous electrolyte secondary battery according to  claim 1 , wherein the positive electrode lead has attached thereto an insulation tape that covers the ceramic layer. 
     
     
       5. The non-aqueous electrolyte secondary battery according to  claim 1 , wherein:
 the positive electrode includes a positive electrode core, a positive electrode mixture layer formed on the positive electrode core, and an exposed core portion which is provided only toward one end in a width direction of the positive electrode core and surrounded on three sides by the positive electrode mixture layer; and 
 the positive electrode lead is joined to the exposed core portion.